So I have been in both situations. Quitting before u lose is not always a bad idea as it may salvage the social contract. Now that being said a opponent that is winning and just wants to table you is pretty crappy and at that point just wants to win and not have a fun time. A over serious opponent or a over stupid acting opponent can lead to a early quit. Not a big deal and as long as the other personal just accepts it and moves on vs drag it out and constantly ask if u are ok or something.